It is known in the art to provide safety helmets for users of vehicles such as motorcycles, or snowmobiles, with an anti-dazzle visor, usually burnished or in any case produced in such a manner as to filter external light, which is pivoted, or constrained, to the outer shell and which, due to an appropriate operating mechanism, is movable between a position of engagement of the front opening of the helmet, i.e. to protect the user's sight, and a position of disengagement from the opening.
More in particular, it is known to produce a safety helmet comprising an outer shell made of rigid synthetic material, coupled integral to a complementary inner shell made of a shock absorbing material, usually an expanded material, in turn associated with a cap for the user's comfort, which is shaped in such a manner to have a front opening which allows the user to see and a lower opening to allow the helmet to be put on.
As it is known, in some safety helmets, known as “open face” helmets, the two openings mentioned above are connected to each other without interruption, while in other helmets they are separated from each other by a specific portion of the outer shell, provided with a corresponding shock absorbing layer, arranged in the user's chin area, and consequently called “chin guard”. In this latter case, production of the chin guard secured integral with the remaining part of the outer shell gives produces helmets which are known as “full face”, while the production of a chin guard that is pivoted, or in any case constrained with at least a degree of freedom, to the outer shell, and which can therefore usually be lifted relative to this latter, defines helmets known as “flip-up full face”.
In any case, regardless of the type of safety helmet considered, it is known to constrain to the outer shell, or optionally to extensions of the chin guard, when this is of the type that can be flipped up, a visor for protection of the user's face which reversibly covers the aforesaid front opening, and, in some cases, it is known to constrain to the outer shell an antidazzle visor, intended to engage at least part of the user's field of vision.
The anti-dazzle visor is usually constrained to the outer shell by means of an operating mechanism which allows the user, through a specific manual control, to move the visor in relation to the outer shell to engage or disengage the front opening of the helmet with the antidazzle visor.
In this regard, there are known different operating mechanisms of the anti-dazzle visor which allow the user to switch, rapidly and easily, from the aforesaid position of engagement of the anti-dazzle visor, usually coinciding with a lowered position relative to the outer shell, to the position of disengagement, usually coinciding with a raised position relative to the outer shell, and vice versa.
It is in fact essential for the person wearing the helmet to be able during travel to move the anti-dazzle visor, rapidly and with simple manual movements, from its position covering the user's field of vision, i.e. of engagement with the front opening of the helmet, to its position out of the user's field of vision, i.e. of disengagement from the front opening, when there are sudden changes in environmental light conditions, for example when entering and exiting a tunnel.
It must be noted that, above all when requiring to change from the position of engagement of the anti-dazzle visor with the front opening of the helmet to the position of disengagement of the anti-dazzle visor, or vice versa, the rapidity with which this change takes place is particularly critical.
It is also essential for the anti-dazzle visor, once arranged in the most suitable position by the user, to remain firmly in this position and not to move accidentally, for example due to vibrations or slight knocks to which the safety helmet is subjected, to the opposite position.
This requirement is particularly important in the case in which the user utilizes the safety helmet provided with the anti-dazzle visor to drive a vehicle at night or to drive a vehicle in conditions of poor environmental light, or in cases in which the anti-dazzle visor is arranged by the user in the raised position of disengagement from the front opening of the helmet. In fact, in these cases accidental lowering, due to vibrations or knocks, of the anti-dazzle visor to the position of engagement with the front opening of the helmet could cause effective problems for the user, while driving the vehicle.
The operating mechanism of the anti-dazzle visor is therefore required to ensure, even when there are vibrations and slight knocks, that it firmly maintains at least the raised position of the anti-dazzle visor, after it has been arranged in this position by the user.
Among the operating mechanisms of the anti-dazzle visor of known safety helmets, those mechanisms that provide for the use of cables for transmitting motion from a control slider, which can be operated manually by the user, to the anti-dazzle visor, are particularly effective and structurally simple.
The international patent application WO 2006/037294 A1, by SCHUBERTH ENGINEERING AG, describes an operating mechanism for an anti-dazzle visor comprising two Bowden cables, i.e. cables capable of transmitting pushing and pulling forces and movements, which have one end thereof connected to at least one control slider, sliding inside a guide integral with the outer shell of the helmet, and the other end thereof connected respectively to lateral operating portions of the anti-dazzle visor. Operation of the control slider, by the user, causes, due to the Bowden cables, transmission of motion from the slider to the anti-dazzle visor, which is thus caused to move from a position covering the field of vision, corresponding to a lowered position, to the position out of the field of vision, corresponding to a raised position, and vice versa.
Although structurally simple., this operating mechanism for the anti-dazzle visor on the one hand proves to be relatively ineffective, given that the speed with which the anti-dazzle visor passes from its position of engagement to its position of disengagement is left to the manual rapidity of the user, and on the other hand the force required by the user to move the control slider, given the presence of the Bowden cables, is substantially equivalent to the force required to raise or lower the anti-dazzle visor, and can therefore represent a possible obstacle to rapid operation of the visor.
The international patent application WO 2010/066278 A1 by LAZER S. A., relates to an operating mechanism to raise or lower an anti-dazzle visor of a safety helmet which comprises a cable, of the flexible or Bowden type, extending between a control slider of the visor, in turn slidable inside a related guide integral with the outer shell of the helmet, and a slider., constrained to two arms of two respective levers, which are in turn integral with lateral end portions of the aforesaid anti-dazzle visor, to cause raising or lowering thereof relative to the outer shell and to the related front opening.
Manual movement of the control slider inside its guide causes, through the motion transmission cable and the kinematic mechanism composed of the slider and of the two levers, movement of the anti-dazzle visor from its lowered position, i.e. covering the user's field of vision, to its raised position, i.e. out of the field of vision, and vice versa.
Although this operating mechanism was designed to allow the user to apply relatively low forces in order to operate the anti-dazzle visor, due to the presence of the two levers employed, it nonetheless has a certain degree of structural complexity and is also cumbersome and difficult to assemble.
Moreover, although the operating mechanism of the anti-dazzle visor described in WO 2010/066278 A1 allows the anti-dazzle visor to be operated by exerting a limited force on the related control slider, it is not provided with specific technical means for rapidly raising this latter in the case of need and does not seem to have any mechanism that ensures the anti-dazzle visor remains stably in its raised position, of disengagement from the front opening of the helmet.
Although the German utility model DE 8534132 U, by WITZMANN does not refer explicitly to a helmet provided with an anti-dazzle visor, it describes a mechanism for raising and lowering the protective visor relative to the front opening of the shell, which includes the use of two flexible motion transmission cables, coupled functionally to a control slider and, respectively, at the lower lateral ends of the visor that act as operating portions of this latter. The helmet also comprises elastic return means, which, interposed functionally between the outer shed and the visor, are structured to push the visor into its raised position, i.e. of disengagement from the front opening of the helmet.
The control slider, which engages slidingly inside a stepped guide adapted to provide a plurality of stable retaining positions for the slider, can be operated by the user in order to lower the visor in opposition to the action of said elastic return means.
Although this visor operating mechanism ensures considerably rapid raising of the visor, it suffers from the same drawbacks already set forth in relation to the international patent application WO 2006/037294 A1, as the force to apply to the slider, given the direct transmission of forces from the slider to the visor, must be equivalent to the force required to raise or lower the visor.